The power of an assembly lies in its “child items” and the mathematical formulas that connect them to the parent takeoff.
Adding a Child Item
Inside the Assembly Editor, you will have a list of the child items that make up the assembly. To add a new one:
1. Click the “+ Add Item” or similar button
2. A new row or dialog will appear, asking for the details of this component
Item Name: A clear description of the material (e.g., “Top/Bottom Track,” “Acoustic Insulation,” “Finishing Labor”)
Units: The unit of measure for this specific item (e.g., “LF” for track, “SF” for insulation, “Hours” for labor)
Waste % (Optional): You can add a waste factor (e.g., 10%) that will be automatically applied to the calculated quantity
Building Formulas
The formula field is where you define the mathematical relationship between the child item and the parent takeoff.
Available Variables: The formula builder will give you access to variables from the parent takeoff. These are the building blocks of your formula.
Parent.Length: The length of the parent linear takeoff
Parent.Area: The area of the parent area takeoff
Parent.Count: The count of the parent count takeoff
Parent.Perimeter: The perimeter of the parent area takeoff
Wall.Height: You can often define custom variables for the assembly, like a wall height, which can then be used in formulas
Mathematical Operators: You can use standard mathematical operators: - +(Addition) - -(Subtraction) - *(Multiplication) - /(Division) - ()(Parentheses for order of operations)
Example Formulas:
• Item: Top/Bottom Track (Units: LF)
Formula: Parent.Length * 2
Explanation: For every foot of wall measured, you need two feet of track (one for the top, one for the bottom)
• Item: Drywall Screws (Units: EA)
Formula: (Parent.Length * Wall.Height * 2) * 1.5
Explanation: Calculate the total surface area of the wall (Parent.Length * Wall.Height * 2) and multiply it by a factor of 1.5 screws per square foot
• Item: Insulation (Units: SF)
Formula: Parent.Length * Wall.Height
Explanation: The square footage of insulation needed is the length of the wall multiplied by its height
Carefully building these formulas is what makes assemblies so powerful, allowing them to automate complex calculations.